Azarian A V, Agatian G L, Galoian A A
Biokhimiia. 1987 Dec;52(12):2033-7.
p-Nitroanilides of amino acids and peptides were used to study the specificity of cathepsins H and B from human and bovine brain, respectively. The specific activity of cathepsin H decreased in the following order: Arg-pNa greater than or equal to Leu-pNa greater than Ala-pNa greater than or equal to Phe-pNa greater than Pro-pNa greater than Glu-pNa; Arg-pNa was split by the enzyme 12 times as fast as Bz-Arg-pNa. Among other oligopeptide p-nitroanilides tested (Ala-Ala, Ala-Leu, Ala-Ala-Ala, Ala-Ala-Leu, Gly-Gly-Leu, Gly-Gly-Phe, Gly-Leu-Phe, pGlu-Phe-Leu, pGlu-Phe-Ala, pGlu-Phe), PGlu-Phe-Leu and pGlu-Phe-Ala appeared to be the best substrates for cathepsin B; Km for hydrolysis were 0.1 mM and 0.165 mM, respectively, kcat were 5.1 and 8.3 s-1, respectively. A comparative study of substrate specificity of cathepsin D and high molecular weight aspartic peptidase with the use of fluorescent substrate with inner fluorescence quenching, Abz-Ala-Ala-Phe-Phe-pNa, revealed that both peptidases hydrolyzed the single bond between two phenylalanine residues, resulting in the increase of fluorescence (4.5-5-fold) of anthraniloyl tripeptide. The Km values for the substrate hydrolysis by cathepsin D and high molecular weight aspartic peptidase were 6.2 microM and 11.2 microM; kcat were 7.2 s-1 and 1.3 s-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
氨基酸和肽的对硝基苯胺用于分别研究人及牛脑内组织蛋白酶H和B的特异性。组织蛋白酶H的比活性按以下顺序降低：精氨酸-对硝基苯胺≥亮氨酸-对硝基苯胺＞丙氨酸-对硝基苯胺≥苯丙氨酸-对硝基苯胺＞脯氨酸-对硝基苯胺＞谷氨酸-对硝基苯胺；精氨酸-对硝基苯胺被该酶裂解的速度是苄基精氨酸-对硝基苯胺的12倍。在所测试的其他寡肽对硝基苯胺（丙氨酸-丙氨酸、丙氨酸-亮氨酸、丙氨酸-丙氨酸-丙氨酸、丙氨酸-丙氨酸-亮氨酸、甘氨酸-甘氨酸-亮氨酸、甘氨酸-甘氨酸-苯丙氨酸、甘氨酸-亮氨酸-苯丙氨酸、焦谷氨酸-苯丙氨酸-亮氨酸、焦谷氨酸-苯丙氨酸-丙氨酸、焦谷氨酸-苯丙氨酸）中，焦谷氨酸-苯丙氨酸-亮氨酸和焦谷氨酸-苯丙氨酸-丙氨酸似乎是组织蛋白酶B的最佳底物；水解的米氏常数分别为0.1 mM和0.165 mM，催化常数分别为5.1和8.3 s-1。使用具有内部荧光猝灭的荧光底物Abz-丙氨酸-丙氨酸-苯丙氨酸-苯丙氨酸-对硝基苯胺对组织蛋白酶D和高分子量天冬氨酸肽酶的底物特异性进行的比较研究表明，这两种肽酶均水解两个苯丙氨酸残基之间的单键，导致邻氨基苯甲酰基三肽的荧光增加（4.5至5倍）。组织蛋白酶D和高分子量天冬氨酸肽酶水解底物的米氏常数分别为6.2 μM和11.2 μM；催化常数分别为7.2 s-1和1.3 s-1。（摘要截短为250字）
